The magnetic dipole moments of the ${cal D}_2$, and ${cal D}_{S_2}$, ${cal B}_2$, and ${cal B}_{S_2}$ heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged meso
ns are larger than that of its neutral counterpart. It is found that the $SU(3)$ flavor symmetry violation is about 10% in both $b$ and $c$ sectors.
Diagonal and transition magnetic moments of the negative parity, spin-1/2 heavy baryons are studied in framework of the light cone QCD sum rules. By constructing the sum rules for different Lorentz structures, the unwanted contributions coming from n
egative (positive) to positive (negative) parity transitions are removed. It is obtained that the magnetic moments of all baryons, except $Lambda_b^0$, $Sigma_c^+$ and $Xi_c^{prime +}$, are quite large. It is also found that the transition magnetic moments between neutral negative parity heavy $Xi_Q^{prime 0}$ and $Xi_Q^0$ baryons are very small. Magnetic moments of the $Sigma_Q to Lambda_Q$ and $ Xi_Q^{prime pm} to Xi_Q^pm$ transitions are quite large and can be measured in further experiments.
The transition magnetic moments between negative parity, spin-1/2 heavy baryons are studied in framework of the light cone QCD sum rules. By constructing the sum rules for different Lorentz structures, the unwanted contributions coming from negative
(positive) to positive (negative) parity transitions are removed. It is found that the magnetic moments between neutral negative parity heavy $Xi_Q^{prime 0}$ and $Xi_Q^0$ baryons are very small. Magnetic moments of the $Sigma_Q to Lambda_Q$ and $ Xi_Q^{prime pm} to Xi_Q^pm$ transitions are quite large and can be measured in further experiments.
The magnetic moments of the negative parity, spin-1/2 baryons containing single heavy quark are calculated. The pollution that occur from the transitions between positive and negative parity baryons are removed by constructing the sum rules from different Lorentz structures.
The magnetic moments of heavy sextet $J^P = {1over 2}^+$ baryons are calculated in framework of the light cone QCD sum rules method. Linearly independent relations among the magnetic moments of these baryons are obtained. The results for the magnetic
moments of heavy baryons obtained in this work are compared with the predictions of the other approaches.
If the $X(3872)$ is described by the picture as a mixture of the charmonium and molecular $D^{ast} D$ states; $Y(3940)$ as a mixture of the $chi_{c0}$ and $D^ast D^ast$ states; and $X(4260)$ as a mixture of the tetra-quark and charmonium sates, their
orthogonal combinations should also exist. We estimate the mass and residues of the states within the QCD sum rules method. We find that the mass splitting among $X$, $Y$ and their orthogonal states is at most $200MeV$. Experimental search of these new states can play critical role for establishing the nature of the new charmonium states.
The magnetic moments of the low lying, negative parity, spin-3/2 baryons are calculated within the light cone QCD sum rules method. The contributions coming from the positive parity, spin-3/2 baryons, as well as from the positive and negative parity
spin-1/2 baryons are eliminated by constructing combinations of various invariant amplitudes corresponding to the coefficients of the different Lorentz structures.
The magnetic dipole G_M(Q^2), electric quadrupole G_E(Q^2), and Coulomb quadrupole G_C(Q^2) form factors, describing the spin-3/2 to spin-1/2 electromagnetic transitions, are investigated within the light cone QCD sum rules. The Q^2 dependence of the
se form factors, as well as ratios of electric quadrupole and Coulomb quadrupole form factors to the magnetic dipole form factors are studied. We also compare our results on the magnetic dipole form factor with the prediction of the covariant spectator quark model.
Using the calculated values of the strong coupling constants of the heavy sextet spin-3/2 baryons to sextet and antitriplet heavy spin-1/2 baryons with light mesons within the light cone QCD sum rules method, and vector meson dominance assumption, th
e radiative decay widths are calculated. These widths are compared with the direct radiative decay widths predicted in the framework of the light cone QCD sum rules.
A new method for calculation of the mixing angle between the hadrons within QCD sum rules is proposed. In this method, the mixing is expressed in terms of quark and gluon degrees of freedom. As an application, the detailed calculation of the mixing a
ngle between heavy cascade baryons Xi_Q and Xi_Q, Q=c,~b is presented and it is found that the mixing angle between Xi_b (Xi_c) and Xi_b (Xi_c) is given by theta_b = 6.4^circ pm 1.8 ^circ (theta_c = 5.5^circ pm 1.8^circ).
